Engineering Highly Reliable Communication and Coordination Systems for High Risk Patients, Referrals, and Tests proposes to establish an Engineering High Reliability Learning Lab (EHRLL) to enhance capacity for innovation and develop highly reliable systems that address communication and coordination challenges that pose patient safety risks at the intersection of primary and specialty care. A five-stage innovation cycle-problem analysis, design, development, implementation, and evaluation-will drive EHRLL efforts to develop highly reliable systems within 19 Harvard-affiliated primary care practices and\their specialty care partners that collectively care for more than 260,000 patients through 1.4 million encounters each year. EHRLL will include an Administrative Core and an Engineering Core to provide a supportive reengineering infrastructure that will incorporate a theory-driven, flexible, shared Learning Program; a multidisciplinary team of experienced investigators and outside Disruptors; and a systematic approach for identifying, designing, developing, spreading, and evaluating patient safety innovation. Three synergistic projects will engage health system-based reengineering and design (R&D) teams in problem analysis and hands-on development, testing, and implementation of highly reliable closed loop systems for high priority primary to specialty referrals (P1 Primary to Specialty Referrals); coordination systems for children with medical complexity undergoing surgery (P2 Complex Perioperative Care); and diagnosis and management systems for new medical conditions in adults with complex care needs (P3 Complex Diagnosis & Management). EHRLL's Overall Specific Aims are: Aim 1: To build a shared infrastructure that comprises an Administrative/Learning Core, an Engineering Core, and multidisciplinary teams to stimulate a systematic approach for patient safety innovation; Aim 2: To engage in three research projects that will apply systems engineering to the development of innovative solutions for improving HIT-supported processes and designing highly reliable systems that are generalizable; Aim 3: To implement and spread redesigned systems across a range of hospital/community-based primary care practices and to test systems' generalizability in alternative settings and conditions; and Aim 4: To assess the impact of redesigned systems on practice, team, provider, and patient outcomes and disseminate findings, tools and resources for national replication.